I personally think that the difference is in the details. Using halo 3 as an example, yeah, split screen is great for having a bunch of mates around and firing bullets/rockets/naids/whatever at them. However, you come up to problems like the old screen-cheating, and also you hear every sound effect caused in the game as if it was made by you. The you switch to live, and you add another dimension. There's no screen-cheating, and a gun firing halfway across the map sounds like it's halfway across the map. Although, split-screen doesn't lag. But, yeah, i agree with general statement, Bring Split-screen Back!